EarthData International collected ALS-50-derived LiDAR over Upper Myakka Florida with
a one-meter post spacing. The period of collection was between 3 October and 12 October
2006. This data set falls in Manatee County. The collection was performed by EarthData
Aviation, using a Leica ALS-50 LiDAR system, including an inertial measuring unit
(IMU) and a dual frequency GPS receiver. This project required six lifts of flight
lines to be collected. The product generated consisted of LiDAR bare earth elevation
models in LAS format. This data set is one component of a digital terrain model (DTM)
for the Southwest Florida Water Management District's FY2005 Digital LiDAR Project
(H048), encompassing approximately 291 square miles across Manatee County. The 2005
LiDAR dataset is comprised of 3-D mass points delivered in the LAS file format based
on the District's 5,000' by 5,000' grid (325 cells). The other DTM component is 2-D
and 3-D breakline features in the ESRI ArcGIS Personal Geodatabase format. In accordance
with the 2005 SWFWMD Topographic Database Design, the following breakline closed water
bodies (lakes, reservoirs, etc) as 3-D polygons; linear hydrographic features (streams,
canals, swales, embankments, etc) as 3-D breaklines; coastal shorelines as 3-D linear
features; edge of pavement road features as 3-D breaklines; soft features (ridges,
valleys, etc.) as 3-D breaklines; obscured vegetation polygons as 2-D polygons; overpasses
and bridges as 3-D breaklines; 1-foot contours for visualization purposes; and island
features as 3-D polygons. Breakline features were captured to develop a hydrologically
correct DTM. Contours (1-foot) were generated from the DTM that meet the National
Map Accuracy Standards for 2-foot contours (FEMA specifications). Bare earth LiDAR
mass point data display a vertical accuracy of at least 0.3-feet root mean square
error (RMSE) in open unobscured areas.

DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National
Oceanic and Atmospheric Administration, U.S. Department of Commerce

Originator

Southwest Florida Water Management District (SWFWMD)

Publisher

DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National
Oceanic and Atmospheric Administration, U.S. Department of Commerce

Date(s)

publication: 2006-12-04

Data Presentation Form:

Digital image

Dataset Progress Status

Complete

Data Update Frequency:

As needed

Purpose:

This project was designed to provide topographic information to the Southwest Florida
Water Management District to support regulatory, land management and acquisition,
planning, engineering and habitat restoration projects.

Use Limitations

These data depict the elevations at the time of the survey and are only accurate for
that time. Users should be aware that temporal changes may have occurred
since this data set was collected and some parts of this data may no longer represent
actual surface conditions. Users should not use this data for critical
applications without a full awareness of its limitations. Any conclusions drawn
from analysis of this information are not the responsibility of NOAA or any of its
partners. These data are NOT to be used for navigational purposes.

Time Period:

2006-10-03 to 2006-10-12

Spatial Reference System:

urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters

Spatial Bounding Box Coordinates:

N: 27.555841

S: 27.176931

E: -081.879906

W: -082.451361

Spatial Coverage Map:

Themes

Bathymetry/Topography

LiDAR

Bare Earth

Terrain

Model

Elevation

Surface

Places

US

Florida

Southwest Florida

Manatee County

Upper Myakka

Use Constraints

No constraint information available

Fees

Fee information not available.

Source Datasets

Upper Myakka Aerial Acquisition

Description of Source: Source Contribution: Aerial Acquisition. EarthData International collected ALS-50-derived
LiDAR over Upper Myakka Florida with a one-meter post spacing using aircraft number
N62912. The period of collection was between 3 October and 12 October 2006. The collection
was performed by EarthData Aviation, using a Leica ALS-50 LiDAR system, serial number
ALS039, including an inertial measuring unit (IMU) and a dual frequency GPS receiver.
This project required six lifts of flight lines to be collected. The lines were flown
at an average of 3000 feet above mean terrain using a pulse rate of 75,000 pulses
per second. Source Type: External hard drive

Temporal extent used:
2006-10-03 to 2006-10-12

Report of GPS Survey Upper Myakka Area, FL

Description of Source: Source Contribution: Ground Control. EarthData International was contracted to provide
mapping services in the Upper Myakka area of Florida. Aerial imagery and LiDAR data
was collected for the project area. EarthData subcontracted the ground survey tasks
to Kevin J. Chappell, Florida PSM License No. LS5818. The Global Positioning System
(GPS) was used to establish the control network. There were a total of 41 stations
occupied for this project. There were 19 new photo control stations, 11 new LIDAR
control stations, 4 temporary GPS base stations, 5 existing NSRS control stations,
1 CORS station, and 1 airborne GPS base station used by the flight crew. The final
network was adjusted using least squares. A free adjustment and constrained adjustment
were performed. The results of the free adjustment indicate an external network accuracy
of better than 3 cm in relation to NAD 1983 1999 and NAVD 1988. The results of the
constrained adjustment indicate an internal network accuracy of better than 3 cm in
relation to NAD 1983 1999 and NAVD 1988. Source Type: Paper

Temporal extent used:
2006-03-07 to 2006-04-13

LiDAR Land Cover Control, Report of GPS Survey

Description of Source: Source Contribution: LiDAR Land Cover QC Survey. EarthData International was contracted
to provide mapping services in the Upper Myakka area of Florida. LiDAR data was collected
for the project area. EarthData subcontracted the quality control survey tasks to
WilsonMiller, Inc. The Global Positioning System (GPS) was used to establish the control
network. There were a total of 93 stations occupied for this project. 64 new LiDAR
land cover control stations, 4 NGS base control stations, 8 FDEP 2005 base control
stations, and 9 NGS control check stations. Source Type: Paper

Temporal extent used:
2007-01-15 to 2007-02-12

Lineage Statement

Lineage statement not available.

Processor

EarthData International

DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National
Oceanic and Atmospheric Administration, U.S. Department of Commerce

The airborne GPS data were processed and integrated with the IMU. The results were
imported into the processing system for use in the LiDAR boresight. The raw LiDAR
data was downloaded onto a production server. The ground control and airport GPS base
station were used in conjunction with the processed ABGPS results for the LiDAR boresight.
The properly formatted processing results were used for subsequent processing.

EarthData has developed a unique method for processing LiDAR data to identify and
remove elevation points falling on vegetation, buildings, and other aboveground structures.
The algorithms for filtering data were utilized within EarthData's proprietary software
and commercial software written by TerraSolid. This software suite of tools provides
efficient processing for small to large-scale, projects and has been incorporated
into ISO 9001 compliant production work flows. The following is a step-by-step breakdown
of the process. 1. Using the LiDAR data set provided by EarthData Aviation, the technician
performs calibrations on the data set. 2. The technician performed a visual inspection
of the data to verify that the flight lines overlap correctly. The technician also
verified that there were no voids, and that the data covered the project limits. The
technician then selected a series of areas from the data set and inspected them where
adjacent flight lines overlapped. These overlapping areas were merged and a process
which utilizes 3-D Analyst and EarthData's proprietary software was run to detect
and color code the differences in elevation values and profiles. The technician reviewed
these plots and located the areas that contained systematic errors or distortions
that were introduced by the LiDAR sensor. 3. Systematic distortions highlighted in
step 2 were removed and the data was re-inspected. Corrections and adjustments can
involve the application of angular deflection or compensation for curvature of the
ground surface that can be introduced by crossing from one type of land cover to another.
4. The LiDAR data for each flight line was trimmed in batch for the removal of the
overlap areas between flight lines. The data was checked against a control network
to ensure that vertical requirements were maintained. Conversion to the client-specified
datum and projections were then completed. The LiDAR flight line data sets were then
segmented into adjoining tiles for batch processing and data management. 5. The initial
batch-processing run removed 95% of points falling on vegetation. The algorithm also
removed the points that fell on the edge of hard features such as structures, elevated
roadways and bridges. 6. The operator interactively processed the data using LiDAR
editing tools. During this final phase the operator generated a TIN based on a desired
thematic layer to evaluate the automated classification performed in step 5. This
allowed the operator to quickly re-classify points from one layer to another and recreate
the TIN surface to see the effects of edits. Geo-referenced images were toggled on
or off to aid the operator in identifying problem areas. The data was also examined
with an automated profiling tool to aid the operator in the reclassification. 7. The
point cloud data were delivered in LAS format. 10 - points in wetlands and ditches,
9 - points in water, 2 - ground points, and 1 - all other.

The NOAA Coastal Services Center (CSC) received the files in LAS format. The files
contained Lidar elevation measurements. The data was in Florida State Plane Projection
and NAVD88 vertical datum. CSC performed the following processing to the data to make
it available within the LDART Retrieval Tool (LDART): 1. The data were converted from
Florida State Plane West coordinates to geographic coordinates. 2. The data were converted
from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid 03. 3.
The LAS data were sorted by latitude and the headers were updated.

The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp
transfer from the NOAA Coastal Services Center. The data are
currently being served via NOAA CSC Digital Coast at http://www.csc.noaa.gov/digitalcoast/.
The data can be used to re-populate the system. The data are archived in LAS
or LAZ format. The LAS format is an industry standard for LiDAR data developed by
the American Society of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless
compressed version of LAS developed by Martin Isenburg (http://www.laszip.org/). The
data are exclusively in geographic coordinates (either NAD83 or ITRF94). The data
are referenced vertically to the ellipsoid (either GRS80 or ITRF94), allowing for
the ability to apply the most up to date geoid model when transforming to orthometric
heights.